Influencing factors and characteristics of nighttime sap flow of Acer truncatum in Beijing mountainous area

2019 ◽  
Vol 39 (9) ◽  
Author(s):  
张婕 ZHANG Jie ◽  
蔡永茂 CAI Yongmao ◽  
陈立欣 CHEN Lixin ◽  
陈左司南 CHEN Zuosinan ◽  
张志强 ZHANG Zhiqiang
Keyword(s):  
Influencing Factors ◽  
Sap Flow ◽  
Mountainous Area

scholarly journals Spatiotemporal variation in global floods with different affected areas and the contribution of influencing factors to flood-induced mortality (1985–2019)

2022 ◽  
Author(s):  
Tian Liu ◽  
Peijun Shi ◽  
Jian Fang
Keyword(s):  
Influencing Factors ◽  
Large Scale ◽  
Human Life ◽  
Flood Frequency ◽  
Spatiotemporal Variation ◽  
Mountainous Area ◽  
Flood Events ◽  
Protection Measures ◽  
Flood Duration ◽  
Level Ii

AbstractFloods are great threats to human life and property. Extensive research has investigated the spatiotemporal variation in flood occurrence, while few have studied the heterogeneity in global flood events of different sizes, which may require different coping strategies and risk reduction policies. In this study, we analysed the spatiotemporal patterns of global flood events with different affected areas (classified in three levels) during 1985–2019 and examined the contribution of different influencing factors to flood-induced mortality using Geodetector. The results show that (1) the increase in global flood frequency was mainly caused by Level II and Level III floods, and the average area affected by flood events has been increasing yearly since 1985. (2) In America and Africa, the frequency of Level III floods has increased monotonically. At the same time, the frequency of Level I floods in Europe and Level II floods in Asia has increased significantly. (3) For Europe and Asia, most of the deaths occurred with Level II floods; while for America and Africa, Level III floods caused the most mortality. (4) The top three factors contributing to the spatial heterogeneity in flood-induced mortality were the affected population, GDP per capita and flood duration. The contribution of each factor varied among the different types of floods. Topographic factors (percentage of mountainous area) magnified flood-induced mortality during extreme events with heavy rainfall, especially for Level III floods. The heterogeneity in flood frequency and flood-induced mortality indicates that flood protection measures should be more targeted. In addition, the increase in large-scale floods (Level III) highlights the need for transregional cooperation in flood risk management.

Analysis on the variation and influencing factors of stem sap flow of Lycium barbarum in arid area

2016 ◽  
Vol 36 (17) ◽  
Author(s):  
徐利岗 XU Ligang ◽  
苗正伟 MIAO Zhengwei ◽  
杜历 DU Li ◽  
鲍子云 BAO Ziyun ◽  
王怀博 WANG Huaibo ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Sap Flow ◽  
Arid Area ◽  
Lycium Barbarum

scholarly journals Spatial Agglomeration Characteristics of Rural Settlements in Poor Mountainous Areas of Southwest China

2020 ◽  
Vol 12 (5) ◽  
pp. 1818 ◽  
Author(s):  
Guanglian Luo ◽  
Bin Wang ◽  
Dongqi Luo ◽  
Chaofu Wei
Keyword(s):  
Influencing Factors ◽  
Research Area ◽  
Mountainous Area ◽  
Cultivated Land ◽  
Rural Settlements ◽  
Mountainous Areas ◽  
Residential Areas ◽  
Spatial Agglomeration ◽  
Agglomeration Effect ◽  
Highly Correlated

The rural settlements in poverty-stricken mountainous areas are the "living fossils" of an economic society with the characteristics of spatial dispersion and are slowly changing. Spatial agglomeration is the development direction of rural settlements. In-depth exploration of the spatial agglomeration characteristics and influencing factors of rural settlements in poverty-stricken mountainous areas is a way to provide a basis for rural settlement restructuring. We selected Pengshui County, a national poverty-stricken county in the southwestern mountainous area of China, as the research area. Spatial buffer and kernel density analysis were used to analyze the agglomeration characteristics of rural settlements and influencing factors. The results show that: (1) The rural settlements are small in scale and the space is evenly dispersed. 55.63% of the rural settlements’ sizes are less than 1000 m2, 84.15% of the rural settlements’ sizes are less than 2500 m2, and 92.81% of the rural settlements are within 200 m. (2) The elevation and slope of topographic factors have a significant agglomeration effect on rural settlements. However, the slope direction has no agglomeration effect. 85.41% of rural settlements (52.75% of rural settlements are gathered between 400 and 800 m above sea level) are gathered at an altitude of 1000 m or less, and 77.59% of rural settlements are gathered with a slope of 6~25°. Additionally, there are few rural settlements with a slope of 0~2°. Moreover, the distribution of residential areas has no agglomeration effect on rural settlements. (3) The cultivated land exerts the most significant effect on rural settlements followed by roads and water sources, while the role of urban land is weak. 99.48% of rural settlements are concentrated in the 100 m area of cultivated land. Therefore, in the poverty-stricken mountainous areas in the southwestern mountainous areas of China, convenient farming is the primary condition for production and living. Rural settlements are highly correlated with cultivated land. Rural settlements are scattered and concentrated with the scattered cultivated land. The rural settlements were leaded by the distribution of cultivated land. Less high-quality cultivated land with less slope were occupied or not by rural residential areas’ people.

scholarly journals Sap flow of Salix psammophila and its principal influencing factors at different slope positions in the Mu Us desert

PLoS ONE ◽  
2019 ◽  
Vol 14 (12) ◽  
pp. e0225653
Author(s):  
Zhiyong Pei ◽  
Shaorong Hao ◽  
Guohui Pang ◽  
Kai Wang ◽  
Tiejun Liu
Keyword(s):  
Influencing Factors ◽  
Sap Flow ◽  
Mu Us Desert

How to differentiate nighttime transpiration and water recharge in nocturnal sap flow?

2020 ◽  
Author(s):  
Zuosinan Chen ◽  
Zhiqiang Zhang ◽  
Lixin Chen
Keyword(s):  
Soil Moisture ◽  
Wind Speed ◽  
Water Loss ◽  
Sap Flow ◽  
Northern China ◽  
Mountainous Area ◽  
Nighttime Transpiration ◽  
Environmental Controls ◽  
Water Recharge ◽  
Semi Arid

<p>Nocturnal sap flow (<em>Q<sub>n</sub></em>) affect not only forest carbon and water budgets but also their responses to climate change as it consists of two ecohydrological and ecophysiological significant components: nighttime transpiration and water recharge. A vapor pressure deficit (<em>VPD</em>) based sap flow partitioning method has been developed to estimate nighttime transpiration, which is normally quantified through the discretely measured nighttime stomatal conductance, from the widely and continuously measured sap flow. However, given the increasing knowledge of <em>Q<sub>n</sub></em> mechanisms, whether <em>Q<sub>n</sub></em> could be partitioning simply by <em>VPD</em> and whether this method is valid in semi-arid regions remain unclear. We measured sap flow of <em>Pinus tabuliformis</em> and <em>Acer truncatum</em> in a middle-aged and a young monoculture forest stand, respectively, in a semi-arid mountainous area of northern China. We found the influence of <em>VPD</em> on <em>Q<sub>n</sub></em> conditioned by soil moisture. Meanwhile, a considerable impact of wind speed on <em>Q<sub>n</sub></em> was observed. In the stands with relatively dry soils, both increased and decreased soil moisture promoted <em>Q<sub>n</sub></em>, which might be due to enhanced nighttime water recharge for two distinct purposes, i.e., capacitance refilling and avoiding hydraulic failures. For these three environmental factors (i.e., <em>VPD</em>, wind speed, and soil moisture) that have been considered most in previous studies, their total effect explained less than 55% of the <em>Q<sub>n</sub></em> variations. This study highlights that physiological influences of <em>VPD</em> on nighttime stomatal water loss were uncertain. Furthermore, it suggests that there could exist considerable nighttime water loss induced by wind, possible region-specific patterns of nighttime water recharge, and limited concurrent environmental controls on <em>Q</em><sub>n</sub>. Our findings are helpful to improve the <em>VPD</em>-based sap flow partitioning method to differentiate nighttime transpiration and water recharge.</p>

Sign in / Sign up

Export Citation Format

Share Document